Ok, typed out a bit of an explanation and then couldn't upload the .xlsx My message was deleted so if there are any questions PM. This is only an outline of what I have planned.

I finished my prototype Catapult. Here is a picture. I used chopsticks, tape, a marker, small piece of paper and rubber band. (The clips aren't necessary but since I taped the ends of where I was supposed to place the rubber bands too much I had to use them)

It shoots at least 8ft. Since I shot it at a wall instead of across the office I'm not sure of it's full potential. The base and height are about the size of a post it. This is just an example, students will create a larger scale one.

The word doc with directions to the catapult is not for the students. This one is for you guys. I will be drawing my directions out and then giving them copies. I do not have access to a scanner so I made this one to explain for you. In the picture I used scotch tape, but with the students we will be using rubber bands. Hopefully you can see the colors in the picture well, they indicate which step, and where each one should be (top or bottom). I'll upload more as I create.

Here is a power point and a quiz about volcanoes aimed at 4th- 6th grade elementary students.After the quiz I will get them to make their own volcanoes with paper mache and make their own volcanic eruption by mixing vinegar, washing up liquid and baking powder based roughly on this:

I should add that this would probably be a two day thing as you need to wait a day for the paper mache volcano to dry before the students could paint it. It would have to be water proof as well for the volcanic eruption experiment( I'm going to get them to cover the volcanoes in pva glue to make them water proof)... but you could include the lessons in a science/ countries/ nature or craft based camp.

Has anyone done a balsa wood bridge project? Where can I find balsa wood in Korea?I was thinking about using wooden chopsticks, but I'm worried that they would make the bridges too strong and impossible to break.

Toothpicks are good! You could also use straws, popsicle sticks, or newspaper. If you use those, I would also give them an additional challenge. Such as, whose bridge can make it from destination A to B AND hold the most pennies. I haven't seen balsa wood here, but if you check a big stationary store, like Papearl, they may have it. That store has a section for building models and what not. I'd also try Gmarket, too.

Ok, I just searched on Naver and had many blogs and whatnot come up in Korean. So, I asked my boyfriend if it was available in Korea and he said, "Oh, it has many." It's called 발사나무 or 뗏목. Hopefully, that helps a bit!

I'd love to try this out with my students. How exactly do you attach the hinge for the throwing-arm? When you say "students will create a larger scale one", what exactly do you mean? Will they use different materials or just full-size wooden chopsticks as a frame?

For the hinge you can use a binder clip! It works really well! You will find your students get very creative with what you give them, too. For example, some of mine skipped the binder clip completely and fabricated a hinge using straws and paperclips.

So for the hinge, I will just use a rubber band. I will make one and post another picture for and example. Yes, for larger scale they will just use whole chopsticks. I broke them in half simply because that day I didn't have enough at my desk. <-- same goes for why you see one marker as the throwing arm, just ran out of chopsticks. A question was asked about what is at the end. I just used a piece of paper to make a small cup to hold the ammo. Students can choose to do this, but I will provide caps from pop bottles, vitamin C bottle, water bottles, ect as well.

Been a bit sick so haven't been able to make it out to the store, will post pictures for bridge and egg drop later this week. Originally I wanted to use popsicle sticks for the bridge, but when I asked my co-teachers (and show picture) they didn't really know what they were. Does anyone know if they are available? I will look for alternatives to chopsticks when I go to the store.

This might be helpful for some like me who couldn't see how the hinge worked in the photo, might be fun to give the kids a basic Idea but then see what they come up with and make a competition out of it. Who ever can knock down a pile of cups or something wins. just an idea.